...And the most important thing to remember when traveling back in time, is that if you mention any of this stuff to the wrong person in the town square ... you'll most likely be burned at the stake for heresy
LOL.. That's what I was going to post, but you beat me to it! )
Heh heh. Reminds me of that saying "In the land of the blind, the one-eyed man is king." when what it should really be is (I'm working on it and haven't decided on the final version yet) "In the land of the blind, the one-eyed man is burned as a witch." After all, he claims to be able to divine this "vision" stuff that nobody else can sense. A "seer" in the literal sense. In a more humane society they might just lock him away for treatment. (I can see the braille Rorschach tests now. "Feel this texture and tell me it what feels like to you" and of course there's no correct answer except that the guy stupid enough to fall for that trick is nuts.)
Anyway, brining modern technology back before it's supported is likely not all it's cracked up to be. For instance I could bring my little FM transistor radio and plenty of batteries, but if it's 1200 AD there's probably nobody broadcasting music. A jet fighter might get you one take-off and revenge strafing run on an enemy, but as soon as you land there's no support crew with jet fuel, radar, lasers, smart bombs, replacement parts, yadda yadda.
What gets me about the whole concept of time travel in movies or Dr. Who or whatever, is that people think if they go to this particular point in history, and change an item, that this is going to ripple up to the point that the time traveler started from(his "present" and other's "future".) But if that were so, then everything everyone did would "ripple" so the time traveler would have not much more influence than anyone else with the power to manipulate events.. like kings or stock market moguls or whoever. Once you go to the "past" it's the "present" and there's really only the "present." If you think about it, if you can travel back and forth, then the stuff has to be all going on at the same time all the time, so it's all really the present anyway.
Either that or I need another injection or Rorschach test.